Lung Cancer Flashcards
Where can lung cancer occur?
Large airways, terminal airways, or within alveoli themselves
What are the main causes of lung cancer?
75% Smoking
Non-smokers: Asbestos, radiation, genetic predisposition, heavy metal exposures
Describe carcinoma development:
Multistep accumulation of mutations that cause disordered growth, loss of cell adhesion, invasion of tissue and angiogenesis, occurring in epithelial and stem cells; different pathways for different tumours, and early stages may be reversible
What are the main local complications of Lung cancer?
Bronchial obstruction
Invasions of local structures
Inflammation of pleura/pericardium
What is bronchial obstruction and what can it cause?
Collapse of distal lung leading to shortness of breath and infections/abscesses/pneumonia/impaired drainage.
What local structures can be invaded and what can this cause?
Vessels/airways causing haemoptysis and superior vena cava syndrome causing venous congestion in the head and arms; dysphagia can result from oesophagus infiltration and Horner’s syndrome if nervous invasion
What can inflam of pleura/pericardium lead to?
Pleuritis/pericarditis with breathlessness and cardiac compromise.
What are the 2 main types of lung cancer?
Non-small cell
Small cell
What are non-small cell tumours?
Includes squamous cell carcinoma, adenocarcinoma and large cell carcinomas
What are small cell tumours?
20% of LCs that grow faster and more aggressively, closely associated with smoking, and turn over rapidly so very chemosensitive; present with advanced disease and often with brain/liver/bones mets so have abysmal prognosis and die within 18mo
What is squamous cell carcinoma?
Carcinoma of tough epithelium that usually lines skin; normal ciliated epithelium becomes irritated by smoke and undergoes metaplasia to become squamous cell epithelia without cilia - more resistant to damage but no cilia to move mucous; dysplasia and disordered growth occurs as mutations are accumulated and becomes carcinoma in situ
What is an Adenocarcinoma?
Glandular epithelium tumours; develops in interstitium and peripheral airways; proliferation of atypical cells along alveolar walls; increase in size and eventually become invasive; adenocarcinoma-in-situ acquire invasive phenotype before invading local tissue and stroma - if can excise early lesions then will cure patient
What are large-cell carcinomas?
Poorly differentiated tumours composed of large cells, with no histological evidence of glandular/squamous differentiation (on EM may show evidence of glandular/squamous/neuroendocrine differentiation)
What are prognoses of Small/Non-small cancers?
Small Cell: 2-4 months untreated, 10-20 months treated (chemoradiotherapy needed)
Non Small Cell: Stage 1 = 60% 5yr survival, Stage 4 = 5% 5yr survival
What is the main treatment for adenocarcinoma?
Surgical excision
What is the main treatment for Small cell carcinoma?
Chemoradiotherapy
What are PDL1 inhibitors?
Programmed death ligand 1
Prevent cancerous cells with new antigens blocking cytotoxic t-cell action to allow them to be destroyed
What do tyrosine kinase inhibitors do?
Stop downstream processes and increase survival time
What is FDG-PET-CT?
Fluorodeoxyglucose actively taken up by rapidly dividing cancer cells; lung and lymph node tissue should not take up, so if have, then cancer probably spread - activity seen on CT and can be used to see spread
What is a Transthoracic CT biopsy?
Needle to lung tissue inserted under CT guidance; real time and high sensitivity yet risk of pneumothorax and bleeding
How can cytology be used to diagnose LC?
Sputum, bronchial washings, pleural fluid and endoscopic fine needle aspiration can be sampled to identify cells that may be cancerous
How is histology used to diagnose LC?
Can do biopsy using bronchoscopy, CT guided biopsy, or mediastinal lymph node biopsy (for staging - surgically); can be done during operation to see if malignant within 15 minutes
Describe the process of TNM staging:
Tumour: TX if immeasurable, T0 if not found, T1-4 if measurable, with a higher number corresponding to a larger size
Nodes: NX if immeasurable, N0 if none affected, N1-3, with a higher number corresponding to more affected nodes
Metastases: MX if immeasurable, M0 if no spread, M1 if has metastasised
What is TNM staging:
Describes the stage using the tumours size, nodes affected and metastases
